upload_file.rb

def save_tokens(access, refresh)
  TokenCred.create!(access: access, refresh: refresh)
end

def upload_zip_to_box
  token_refresh_callback = lambda { |access, refresh, identifier| save_tokens(access, refresh) }
  client = Boxr::Client.new(TokenCred.last.access,
                            refresh_token: TokenCred.last.refresh,
                            client_id: ENV['CLIENT_ID'],
                            client_secret: ENV['CLIENT_SECRET'],
                            &token_refresh_callback)

  folder = client.folder_from_path('/images')
  file = client.upload_file(Rails.public_path.join('goodsImages.zip').to_s, folder)
  updated_file = client.create_shared_link_for_file(file, access: :open)
  puts "URL of the uploaded file is: #{updated_file.shared_link.url}"
end